Questioning Encore Pro data accuracy

[Dale92]

Has anyone here taken the time to do a test of Encore Pro software by running their CPAP unit while they are awake for an extended period of time say 2 to 4 hours and examine the data to see if it gives false readings for obstructive apneas or hyponeas? I am running the REMstar Pro 2 C-Flex.

The reason I am questioning this is I have had the software since mid February of this year and my numbers are always high for AHI usually from 5.5 to 10 with no changes in my perceived sleep quality. My 2nd sleep study lowered my pressure to 10 from 18 after getting my dental appliance and I have watched the numbers jump around daily. I have raised my pressure from 10 to 13 and the numbers keep bouncing in the same area usually 7 to 9ish for AHI totals. Now I sometimes do not fall to sleep for almost an hour depending on the night and when I examine the data the machine records that I have had several events during the time I was awake. It is entirely possible that I could have momentarily drifted off to sleep and re-awakened not noticing the brief nod so I am wondering if anyone has spent time in front of the TV or reading etc. fully awake and checked the data to see if normal breathing patterns are registered as apneas?

I am currently recuperating from carpel tunnel surgery on my left hand and awaiting the surgery on my right hand so I have a little free time so if no one has tested the software I will set aside an afternoon shortly on a rainy day and hook up for a 4 hour test run to see if my numbers read zero obstructive apneas and zero hypopneas as they should.

Dale

[NightHawkeye]

. . . I am wondering if anyone has spent time in front of the TV or reading etc. fully awake and checked the data to see if normal breathing patterns are registered as apneas?

I recall that DSM, and possibly others, have commented on apneas registering while awake. I've also observed this in my own data because I'm often awake for a while before getting up in the morning. One's breathing pattern while awake is somewhat different than while asleep.

I will say that generally the apneas showing in Encore Pro while I'm asleep tend to be real, as corroborated by oximeter data. Hypopneas in the Encore Pro data, however, I have much less faith in. That may just be because mine run fairly high for some reason though.

Regards,
Bill

[roztom]

Dale:

The software responds to breathing irregularities by analyzing the wave form.

I'm sure f you rummage around the site you can find the Respironics software patent and get an idea of how/why it responds. Check Rested Gal's links at the top of the page.

When I strap on I get Snores and Hypop's & sometime OSA'a even when I just srap-on - so I know I'm still awake.

No, the data is not perfect - it will give you a ballpark idea of where you're at - it's better than nothing. The key is the lowest overall numbers (AHI) and how you feel.

Best,

Tom

[Wulfman]

Dale,

Derek did some tests about a year ago concerning whether Encore Pro gave false readings on snoring.

If you're going to test it when you're awake, you will most assuredly be able to get it to give false readings. You have to take these figures with a "grain of salt". The truer results SHOULD be when a person is asleep. Since most of this data is based on air flow sensor interpretations, there are still going to be some false readings.....but probably not as many. Mainly, it's a "benchmark" type of thing, to measure over time, for your sleeping hours.
Beats having to go back to a sleep lab periodically and get all wired up and trying to sleep with all that stuff on.

Does that make sense?

Den

[Dale92]

Thanks to you all for your replys.

Yes Den,Tom and Bill that does make sense. I guess I get a little caught up sometimes in trying to get the "best" results on the software and forget it is better that I am sleeping well and feel better during the day.

Dale

[rested gal]

Dale, it's also very possible that when you're relaxed your airway can collapse a little (or a lot) even while you're still awake.

Just sitting right here, if I deliberately relax my throat as much as possible, it slams shut.

That's one of the things that made me realize I had OSA and needed to try CPAP. I could feel the closure start to happen when I was waiting to fall asleep but was still awake. Then when I experimentally deliberately made my throat relax and felt it close off instantly, I was convinced.

[Snoredog]

I have found the Remstars to be very sensitive when it comes to detecting events, just because it records them on reports doesn't mean it responds to them.

A high snore or mask leak index could indicate mouth breathing... could be why your doctor suggested a new mask. The snores the Remstar detects are inaudible.

Most people snore with their mouth open.

[Sleepless in St. Louis]

I too was (and still am somewhat) skeptical about the correlation between what the software reports and what is really happening. Without any way to prove it with hard data, I can tell that the numbers tend in the correct direction, measured by how I feel when the numbers show a less than restful nights sleep. I look at this as directional, and not concrete data simply becasue the machine can not actually measure an apnea or hypop but can only analyze how the machine "sees" your breathing by looking at patterns and comparing them to what the software thinks is happening. In other words, it's an indirect measurement as oppossed to all the actual data they can collect with the various electrodes at your sleep clinic.

Here's an example of how a machine can be fooled, at least this is my speculation. My data for last night shows a whole bunch of apneas for early morning hours, when I know for a fact that I was awake with the mask still on. But, what I did was pull the blanket over my head to block out the light in hopes that I would fall back asleep to take advantage of the last half an hour before the alarm goes off. That period of time is full of apneas at least according to the machine. I think that it was detecting a change in pressure caused by the restriction of my covers semi-blocking the flow of air out the vents of my Swift interface. The machine interprets that flow limit as an apnea.

If this is what really happened, it makes me wonder how many apneas the machine reported because I was sleeping on my stomach with the exhaust ports too close to the bed sheet, tricking my machine into reporting a restriction that was not actually in my windpipe etc.

So, the data is not perfect and should be taken with a grain of salt. But, it's better than nothing and I think it's useful for picking up changes to your therapy over a longer period of time. Any one given night's data could include a certain amount of false readings. Just my .02.

[ufo13]

Sleepless in St. Louis:

What you say in your post makes perfect sense to me! Pretty simple isn't it! Also agree with all the other POSTS above!


Best to all,

Steve,
ufo13

[snoozalot]

To me, it's kind of like weighing yourself at home and then again at the Dr's office. The numbers will never match. In fact, if you used 5 scales, they probably all be different.

As others have posted, the important thing is the direction, just as in weight loss. The numbers are relative.

[Dale92]

Thanks for the replys! To Rested Gal I didn't think of that but I also close off my airway when awake by relaxing. Even though I had a Uvulectomy I still have a lot of tissue up there and when I totally relax my jaw and throat I tend to close my airway so that is a possibility.

Sleepless in St. Louis, it never crossed my mind that rolling around in bed and maybe blocking a vent hole partially could alter what the software is reading but it does make sense now that you bring it to my attention.

I appreciate everyone who took the time to respond. My biggest concern was not just what the numbers read but that they seem to go up no matter what I did as far as pressure ajustments. I never thought about how I slept during the night could affect what the numbers would say. It may be my apneas have been up or it may be just the software picking up my acrobatics during my ever so restful sleep:)

I returned my machine to a pressure of ten as was prescribed by my second sleep study since I felt no better or nor worse on any higher pressure.

Slightly digressing I sleep very well and it seems to be satisfying until I am up for a hour or so. Then I am back to the yawns and a slightly less foggy brain. Thanks to another doctor that examined me for depression and realizing it was mainly symptoms from my OSA she started my on Provigil. I have actually been awake for the last couple of months and have been able to get projects done at home after having worked 8 hours at my normal job. I know that this drug is not for everyone and I do not like having to be on medication but I have to admit it has really helped me start to experience life again!

thanks again

Dale

[Guest]

Sleepless in St. Louis wrote:

Here's an example of how a machine can be fooled, at least this is my speculation. My data for last night shows a whole bunch of apneas for early morning hours, when I know for a fact that I was awake with the mask still on. But, what I did was pull the blanket over my head to block out the light in hopes that I would fall back asleep to take advantage of the last half an hour before the alarm goes off. That period of time is full of apneas at least according to the machine. I think that it was detecting a change in pressure caused by the restriction of my covers semi-blocking the flow of air out the vents of my Swift interface. The machine interprets that flow limit as an apnea.

If this is what really happened, it makes me wonder how many apneas the machine reported because I was sleeping on my stomach with the exhaust ports too close to the bed sheet, tricking my machine into reporting a restriction that was not actually in my windpipe etc.

So, the data is not perfect and should be taken with a grain of salt. But, it's better than nothing and I think it's useful for picking up changes to your therapy over a longer period of time. Any one given night's data could include a certain amount of false readings. Just my .02.

You need to locate the Respironics patent, it explains how the machine detects and responds to events. Reading it you will learn that it stores a "series" of breathing patterns in memory, not just one or two then when it sees a similar pattern it responds with pressures found to relieve it. The point is, it is very hard to "fake" out the machine into a response because it may sample and use like 10 breath cycles for that particular pattern, way too many for the avg. person to try and simulate. It is very easy for these machines to determine what your normal flow rate is.

We have more apnea events in the morning because we seem to dream more in REM during those hours.

[Sleepless in St. Louis]

You need to locate the Respironics patent, it explains how the machine detects and responds to events. Reading it you will learn that it stores a "series" of breathing patterns in memory, not just one or two then when it sees a similar pattern it responds with pressures found to relieve it. The point is, it is very hard to "fake" out the machine into a response because it may sample and use like 10 breath cycles for that particular pattern, way too many for the avg. person to try and simulate. It is very easy for these machines to determine what your normal flow rate is.

We have more apnea events in the morning because we seem to dream more in REM during those hours.

Please permit me to challange this. I'm sure what you're saying is true, but the point I was trying to make is that the machine still cannot tell if what it is seeing is an apnea or not. It only knows that the established pattern has changed and it's forced to do a "best fit" to what it sees, then calling it an apnea, a hypop, etc. Say my cat (just for example, I don't have a cat) were to lie down on my hose (no jokes please). The machine may interpret that as an apnea when it was truly a "feline induced event". Again, the machine can only analyze and guesstimate. It cannot see or meausure what's going on in my body, patented technology or not.

[mesaboog]

In reading the posts above and reviewing my first download data, it does appear that most of the Apnea's recorded by Encore Pro (in my case) are in the 30 - 45 min upon turning on the machine, after returning from a bathroom trip, or in the morning while waking up. I am correlating these events to fidgeting with the mask which disrupts the pattern of the machine and is recorded as an apnea. I can feel the machine trying to sync with my breathing in these time periods after I have re-adjusted the mask and broken the sync.

If I were to remove awake data, my AHI would be much lower. I was immediately concerned that my overall OAI for my initial 14 days was 5.1. But in further analysis, the majority of OA events took place in the periods when I was awake and knowingly fidgeting with the mask.

[Linda3032]

Mesaboog, that may very well be the reason. But, if you are using an Apap, then another reason could be that your minimum pressure is too low.